Carriage apparatus, printing apparatus, and control method thereof

ABSTRACT

A carriage apparatus characterized by comprising a carriage configured to reciprocally move in a predetermined direction, a first motor arranged on a side of one end of a range of movement of the carriage and configured to drive the carriage, a second motor arranged on a side of the other end of the range of movement of the carriage, configured to drive the carriage, and has the same kind of driving characteristics as driving characteristics of the first motor, detection means for detecting a position of the carriage related to the predetermined direction, and control means for controlling driving of the first motor and the second motor by feeding back a detection result detected by the detection means.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a carriage apparatus, a printingapparatus, and a control method thereof and, more particularly to, forexample, a printing apparatus that performs printing by discharging inkto a print medium while reciprocally scanning a carriage on which aninkjet printhead is mounted, and a method of controlling the printingapparatus.

Description of the Related Art

In recent years, there is increasing demand for improved productivityand the image quality of inkjet printing apparatuses that performprinting by reciprocally moving a carriage on which a printhead ismounted and discharging ink from the printhead to a print medium such asa print sheet. More specifically, although a printhead increasinglytends to have a longer printing width and a higher nozzle packingdensity and the weight of the printhead has increased accordingly, thereis demand for a carriage which incorporates such a printhead to bedriven at a high speed and with accuracy.

There has been mainly employed, as a method of driving such a carriage,a method of scanning a carriage by arranging a large motor with a highoutput at the end on one side and a driven pulley at the end on theother side of a range of movement of the carriage and suspending atiming belt between the motor and the driven pulley. However, ingeneral, since the market distribution scale of a high output motor issmall, the cost of a high output motor tends to greatly increase. Tosolve this problem, a carriage driving method in which a DC motor isinstalled on the end on one side and a stepper motor is installed on theend on the other side of the range of movement of a carriage has beenproposed (Japanese Patent No. 3604994).

However, in the related-art described above, control commandscorresponding to the respective characteristics of the DC motor and thestepper motor need to be provided. In this manner, the control methodbecomes complicated if different types of motors are to be used to drivea heavyweight carriage at a high speed and with accuracy, and it becomesdifficult to obtain good control responsiveness and good controlstability.

SUMMARY OF THE INVENTION

The present invention provides a carriage apparatus, a printingapparatus, and a control method thereof that allow a carriage to bedriven without complicating the control method.

One of the aspects of the present invention provides a carriageapparatus characterized by comprising a carriage configured toreciprocally move in a predetermined direction, a first motor arrangedon a side of one end of a range of movement of the carriage andconfigured to drive the carriage, a second motor arranged on a side ofthe other end of the range of movement of the carriage, configured todrive the carriage, and has the same kind of driving characteristics asdriving characteristics of the first motor, detection means fordetecting a position of the carriage related to the predetermineddirection, and control means for controlling driving of the first motorand the second motor by feeding back a detection result detected by thedetection means.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments (with reference to theattached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are external perspective views each showing a schematicarrangement of an inkjet printing apparatus according to arepresentative embodiment of the present invention;

FIG. 2 is an explanatory view showing a structure of a periphery of acarriage of the printing apparatus;

FIG. 3 is a block diagram showing a motor control arrangement of aprinting apparatus according to the first embodiment;

FIG. 4 is a timing chart showing a carriage speed profile and thedetails of control signals included in a control line 110 and;

FIGS. 5A to 5C are views for explaining the relationship between alinear scale and an encoder sensor and encoder signals output from theencoder sensor;

FIG. 6 is a diagram showing the more specific details of a relationshipbetween the control line 110, a control unit 102, a driving unit 103,and phase information 108 from a carriage motor 104;

FIG. 7 is a view showing a truth table of control signals of the controlunit 102;

FIG. 8 is a flowchart showing operation control of carriage (CR) motors;

FIG. 9 is a block diagram showing the motor control arrangement of aprinting apparatus according to Modification 1 of the first embodiment;

FIG. 10 is a diagram showing the more specific details of a relationshipbetween the control line 110, the control unit 102, a driving unit 111,a driving unit 112, and the phase information 108 from the carriagemotor 104;

FIG. 11 is a block diagram showing the motor control arrangement of aprinting apparatus according to Modification 2 of the first embodiment;

FIG. 12 is a diagram showing the more specific details of a relationshipbetween a control line 201, a control line 202, a control unit 130, acontrol unit 131, the driving unit 111, the driving unit 112, the phaseinformation 108 from the carriage motor 104, and phase information 109from a carriage motor 109;

FIG. 13 is a block diagram showing the motor control arrangement of aprinting apparatus according to the second embodiment;

FIG. 14 is a flowchart showing a carriage motor confirmation sequence;

FIG. 15 is a flowchart showing a carriage motor confirmation sequenceaccording to Modification 1 of the second embodiment;

FIG. 16 is a block diagram showing the motor control arrangement of aprinting apparatus according to Modification 2 of the second embodiment;

FIG. 17 is a block diagram showing the motor control arrangement of aprinting apparatus according to Modification 3 of the second embodiment;and

FIG. 18 is a perspective view showing the structure near the recoveryunit of the printing apparatus shown in FIG. 1, and is a view showing astate in which the recovery unit has been removed from the printingapparatus.

DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will be further describedin detail with reference to the accompanying drawings. Note that thefollowing embodiments do not limit the invention according to the scopeof the appended claims. Although a plurality of features are describedin the embodiments, not all of the features are essential to theinvention and the plurality of features may arbitrarily be combined.Furthermore the same reference numerals denote the same or similar partsin the accompanying drawings, and a repetitive description thereof willbe omitted.

Note that in this specification, the term “printing” (to be alsoreferred to as “print” hereinafter) not only includes the formation ofsignificant information such as characters and graphics, regardless ofwhether they are significant or insignificant. Furthermore, it broadlyincludes the formation of images, figures, patterns, and the like on aprint medium, or the processing of the medium, regardless of whetherthey are so visualized as to be visually perceivable by humans.

In addition, the term “print medium” not only includes a paper sheetused in common printing apparatuses, but also broadly includesmaterials, such as cloth, a plastic film, a metal plate, glass,ceramics, wood, and leather, capable of accepting ink.

Furthermore, the term “ink” (to also be referred to as a “liquid”hereinafter) should be extensively interpreted similarly to thedefinition of “printing (print)” described above. That is, “ink”includes a liquid which, when applied onto a print medium, can formimages, figures, patterns, and the like, can process the print medium,or can process ink (for example, solidify or insolubilize a coloringmaterial contained in ink applied to the print medium).

Further, a “nozzle” generically means an orifice or a liquid channelcommunicating with it, and an element for generating energy used todischarge ink, unless otherwise specified.

<Outline of Printing Apparatus (FIGS. 1A, 1B, and 2)>

FIGS. 1A and 1B are outer appearance views showing the schematicarrangement of an inkjet printing apparatus according to arepresentative embodiment of the present invention. FIG. 1A shows aperspective view showing the schematic arrangement of an inkjet printingapparatus 100 (to be referred to as a printing apparatus hereinafter),and FIG. 1B shows a top view thereof.

In addition, FIG. 2 is an explanatory view showing the structure of theperiphery of a carriage of the printing apparatus.

In FIGS. 1A, 1B, and 2, arrows X, Y, and Z indicate the front-and-reardirection (a depth direction), the left-and-right direction (widthwisedirection as the longitudinal direction of the apparatus), and theupper-and-lower direction (the vertical direction or the direction ofgravity), respectively. In addition, “F”, “B”, “L”, and “R” indicate thefront side, the rear side, the left side, and the right side,respectively.

The printing apparatus 100 includes a printing unit including aprinthead 2 and a carriage 3. A plurality of discharge orifices(nozzles) are formed on the printhead 2, and a plurality of channels areformed in the printhead 2 so as to communicate with the respectivedischarge orifices. An inkjet-method energy generating element such as aheater, a piezoelectric element, or the like is arranged in each of theplurality of channels, and ink droplets are discharged from thecorresponding discharge orifice by the inkjet method. Ink tanks 5containing inks to be supplied to the printhead 2 are arranged inpositions separate from the printing unit. Note that the printing methodis not limited to the inkjet method, and a printhead of another printingmethod may also be used.

A carriage motor 104 and a carriage motor 107 each connected to adriving pulley 19 are arranged at both ends of a range of movement ofthe carriage 3. A description will be made here by assuming that thecarriage motor 104 and the carriage motor 107 arranged at both ends havesimilar characteristics including the driving pulleys 19. A timing belt7 is suspended and arranged between the two carriage motors, and thecarriage 3 is attached to a part of the timing belt 7. The carriage 3can be made to scan by these components. By using two carriage motors todrive the carriage 3 in this manner, it will be possible to increase theoutput more than when a carriage is driven by a single carriage motor,and even a heavyweight carriage will be able to be scanned at a highspeed.

The printing apparatus 100 also includes a position detection mechanismfor detecting the position of the carriage 3. Such a position detectionmechanism includes a linear scale 13 extending in a carriage scanningdirection and an encoder sensor 14 which is mounted on the carriage 3and reads slits provided in the linear scale 13. The positioncontrol/speed control of the carriage 3 can be performed by feeding backan encoder signal detected by this position detection mechanism.

The carriage 3 on which the printhead 2 is mounted is guided by a guiderail 11 and a guide rail 12 and is supported by a main body of theprinting apparatus 100. The guide rail 11 and the guide rail 12 aresupported by a main body frame 10. The carriage 3 reciprocally movesalong an extending direction of the guide rail 11 and the guide rail 12.A direction in which the carriage 3 is scanned toward the L side and adirection in which the carriage 3 is scanned toward the R side in FIGS.1A, 1B, and 2 will be described as “a forward direction” and “a reversedirection”, respectively, hereinafter. In addition, regardless of theforward direction and the reverse direction, a direction in which thecarriage 3 moves will be referred to as a main scanning direction.

A rolled sheet 1 as a print medium is set in a sheet feeding unit. Theprinting apparatus 100 includes a conveyance roller 4 which isrotationally driven and a pinch roller 9 which rotates by being drivenby the conveyance roller 4. A platen 6 supports the sheet 1 in aposition facing the printing unit. The sheet 1 is conveyed in a state inwhich the sheet 1 is sandwiched between the conveyance roller 4 and thepinch roller 9. A printing operation of discharging ink toward the sheet1 on the platen 6 while the carriage 3 on which the printhead 2 ismounted is moved in the main scanning direction, and a conveyingoperation of conveying the sheet 1 in a sheet conveyance direction(sub-scanning direction) stepwise are performed. An image is printed ona sheet in accordance with a serial printing method by repetitivelyperforming the printing operation and the conveying operation.

Note that the reference of the carriage 3 and the sheet is set on theside of the ink tanks 5. That is, the position of the end portion of thesheet on the reference side will not change even if the width of thesheet changes. In addition, a recovery unit 120 is arranged on thereference side. The recovery unit 120 includes a cap 121 for sealing thesurfaces of discharge orifices formed in the printhead 2. An in-capabsorbing member is provided in the cap 121 to receive and absorb inkdischarged during a preliminary ink discharge operation (preliminarydischarge) performed to prevent discharge failure of the printhead 2.

FIG. 18 is a perspective view showing a structure near the recovery unit120 of the printing apparatus 100 shown in FIG. 1. FIG. 18 shows a statein which the recovery unit 120 is attached to the printing apparatus100.

The cap 121 for sealing the surfaces of the discharge orifices formed onthe printhead 2 is provided on the recovery unit 120 as described above.An in-cap absorbing member is provided in the cap 121 to receive andabsorb ink discharged during a preliminary ink discharge operation(preliminary discharge) performed to prevent discharge failure of theprinthead 2.

The cap 121 is connected to a suction pump and a tube, and sucks ink orair from the surfaces of the discharge orifices of the printhead 2, asneeded, to clean the discharge orifices and to remove air accumulated inthe printhead. A wiper member is also provided to remove ink or dirtthat has adhered to the surfaces of the discharge orifices of theprinthead 2. In addition, a discharge failure detection unit is arrangedbeside the recovery unit 120, and the discharge failure detection unitincludes a sensor for detecting whether ink is being correctlydischarged from each discharge orifice of the printhead 2.

Since the recovery unit 120 will perform a recovery operation on theprinthead 2 which is mounted on the carriage 3, the recovery unit 120will be arranged outside the width of a sheet 1 but also be arrangedinside the scanning range of the carriage 3. As shown in FIG. 18, amotor support member 201 is attached to a motor attachment plate 202,and is formed to be integrally attachable/detachable as a tensionapplying unit 200 for applying tension to the timing belt 7. Inaddition, the tension applying unit 200 is fixed to the main body frameby screws 206. Also, a protruding shape 10 b and a protruding shape 10 dare provided in the motor attachment plate 202. The tension applyingunit 200 also includes the carriage motor 107 and is arranged outsidethe scanning range of the carriage 3.

Hence, as shown in FIG. 18, the tension applying unit 200 is arrangedoutside the recovery unit 120, which is arranged inside the scanningrange of the carriage 3, and the tension applying unit 200 is fixed tothe main body frame by the screws 206. Furthermore, as is obvious fromFIG. 18, the ink tanks 5 and the recovery unit 120 are arranged on thereference side of the carriage 3.

Each of a tube 73R and a tube 73L is a tube formed by a plurality offlexible ink tubes for supplying inks of a plurality of colors from theink tanks 5 fixed to the side of the main body of the printing apparatus100 to the printhead 2 on the carriage 3. The tube 73R is provided sothat its R side will be U-shaped in the Y direction by fixing its oneend to the carriage 3 and its other end to a connecting member 70 whichis fixed to the side of the main body of the printing apparatus 100. Ina similar manner, the tube 73L is also provided so that its L side willbe U-shaped in the Y direction. In this example, the tube 73R and thetube 73L are installed to have the same number of bundled tubes, thesame length, the same material, and the like as each other, and haveonly different curving directions from each other.

In addition, to guide the deformation of the tube 73R and the tube 73Lwhich accompanies the reciprocal movement of the carriage 3, theprinting apparatus 100 includes tube holding members 78R and 78L. Inthis example, each tube holding member is a chain link (cable carrier)formed by connecting a plurality of link members. Each link member is aring-shaped member in which a tube can be inserted, and adjacent linkmembers are pivotably connected to each other about an axis in the Xdirection. Each of the tube holding members 78R and 78L is curved in a Ushape in the Y direction and deforms by changing a curving portion so asto follow the reciprocal movement of the carriage 3. In this example,the tube holding members 78R and 78L have the same number of connectedlink members. The tube 73R is inserted in the tube holding member 78R,and the tube 73L is inserted in the tube holding member 78L.

Several embodiments of a more specific method for driving the carriage 3by using the printing apparatus 100 according to the above-describedarrangement will be described next.

First Embodiment

FIG. 3 is a block diagram showing the motor control arrangement of aprinting apparatus according to the first embodiment.

A carriage motor 104 and a carriage motor 107 shown in FIG. 3 arebrushless DC motors. A CPU 101 controls, via a control line 110, acontrol unit (controller) 102 based on a signal from a common encodersensor 14. Also, the control unit 102 controls a driving unit (motordriver) 103 based on signals from the control line 110 and phaseinformation 108 from the carriage motor 104. Subsequently, each of thecarriage motor 104 and the carriage motor 107 performs a predeterminedoperation based on a driving signal from the driving unit 103. A ROM 120stores pieces of information that indicate the speed ofacceleration/deceleration corresponding to the print medium or a printmode, a constant speed, a distance until a stop, and the like.

Details of the motor control arrangement shown in FIG. 3 will bedescribed next with reference to FIGS. 4 to 7.

FIG. 4 is a view showing a carriage speed profile and the details ofcontrol signals included in the control line 110.

The control line 110 includes, as shown in FIG. 4, a reset signal(Reset), a direction signal (Direction), a PWM signal, and a brakesignal (Brake), and the carriage motor 104 and the carriage motor 107are controlled by the same control signal.

The reset signal controls whether each carriage motor is to be operated.In this embodiment, each carriage motor will not be able to operate whenthe reset signal is at high level (a period R-A in FIG. 4), and eachcarriage motor will be able to operate when the reset signal is at lowlevel (a period R-B in FIG. 4).

The direction signal controls the direction of the operation of eachcarriage motor. In this embodiment, the carriage 3 will move in theforward direction when the direction signal is at high level (a periodD-A in FIG. 4), and the carriage 3 will move in the reverse directionwhen the direction signal is at low level (a period D-B in FIG. 4). Notethat an operation in the forward direction and an operation in thereverse direction are, more specifically, operations in the rotationdirections of each carriage motor, and the forward direction and thereverse direction have opposite rotation directions from each other.Each carriage motor is formed by a three-phase coil and can change theaforementioned rotation direction by controlling a voltage supplied toeach of coil voltage terminals U, V, and W shown in FIG. 6.

The PWM signal controls the amount of energy supplied to each of thecoil voltage terminals U, V, and W of each carriage motor. The amount ofenergy supplied to each coil voltage terminal is determined by an ON/OFFratio (to be referred to as a PWM duty cycle hereinafter). The coilvoltage will increase as the PWM duty cycle increases, thereby causingthe carriage motor to rotate at a higher speed. In this embodiment,assume that a predetermined cycle is 10 kHz (each broken line intervalshown in FIG. 4). A period in which the PWM duty cycle is greater than50% is an acceleration period (a period P-A in FIG. 4) of each carriagemotor, a period in which the PWM duty cycle is 50% is a constant speedperiod (a period P-B in FIG. 4), and a period in which the PWM dutycycle is less than 50% is a deceleration period (a period P-C in FIG.4).

The brake signal is a signal for stopping each carriage motor, and stopcontrol is performed when the brake signal is at high level in thisembodiment (a period B-A in FIG. 4). More specifically, the operation ofthe carriage 3 will be stopped by controlling the voltage applied toeach of the coil voltage terminals U, V, and W of each carriage motor sothat the movement of the carriage 3 will change to an operation in thereverse direction if the carriage 3 is moving in the forward direction.

The control time and the control waveform of each of the directionsignal, the PWM signal, and the brake signal described above aredetermined based on a signal from the common encoder sensor 14. Here,the signal (encoder signal) from the encoder sensor 14 is generated by alinear scale 13 and the encoder sensor 14 shown in FIG. 2.

FIGS. 5A to 5C are views for explaining the relationship between thelinear scale and the encoder sensor, and the encoder signal output fromthe encoder sensor.

By causing, as shown in FIG. 5A, the encoder sensor 14 to read the slitsformed on the linear scale 13, two encoder signals (an A phase and a Bphase) whose phases are shifted from each other by 90° are generated asshown in FIG. 5B. Each signal is input to the CPU 101, and the number ofpulses of the signal can be counted to obtain the position of thecarriage 3 that has been driven by the carriage motors. In addition, thespeed of the carriage 3 can be calculated based on the cycle of eachencoder signal. Furthermore, the direction of movement of the carriage 3can be calculated from the phase state of each encoder signal.

In this embodiment, as shown in FIG. 5C, it will be determined that thecarriage is moving in the forward direction if the A-phase signal riseswhen the B-phase signal is at high level, and it will be determined thatthe carriage is moving in the reverse direction if the A-phase signalrises when the B-phase signal is at low level.

FIG. 6 is a diagram showing the more specific details of a relationshipbetween the control line 110, the control unit 102, the driving unit103, and the phase information 108 from the carriage motor 104.

FIG. 7 is a view showing a truth table of the control signals of thecontrol unit 102.

The driving unit (driver) 103 is formed by, as shown in FIG. 6, powersupply lines VM, FETs 141 to 143, and FETs 144 to 146, and is connectedto the carriage motor 104 and the carriage motor 107. Also, the phaseinformation 108 is formed by three signals, and the signals are input toterminals H1, H2, and H3 of the control unit (controller) 102.

The phase information 108 indicates the position information of the coilin the carriage motor 104, and a signal of 0 (low voltage) or 1 (highvoltage) will be input. Each of terminals HA to HC and terminals LA toLC of the control unit 102 is connected to the gate of the correspondingone of FETs 141 to 146 of the driving unit 103, and the driving of eachFET is controlled by a signal of 0 (low voltage) or 1 (high voltage).The outputs from the terminals HA, LA, HB, LB, HC, and LC of the controlunit 102 are controlled by the combinations of the phase information 108and the control signals as shown in FIG. 7. As a result, the FETs 141 to143 and the FET 144 to FET 146 will be set to ON or OFF and the voltagesapplied to the coil voltage terminals U, V, and W of each carriage motorwill be controlled, thus allowing the carriage to operate at anarbitrary speed and in an arbitrary direction.

The operation of the carriage motors having the arrangement describedabove with reference to FIGS. 4 to 7 will be described next withreference to a flowchart.

FIG. 8 is a flowchart showing the operation control of carriage (CR)motors. An example in which the two carriage motors 104 and 107 arecontrolled to move the carriage 3 in the forward direction will bedescribed here. Note that the control for moving the carriage 3 in thereverse direction will also be performed in a similar manner.

When the control to operate the carriage motors in the forward directionis started, the CPU 101 sets, in step S801, the reset signal to lowlevel (the period R-A in FIG. 4). Next, in step S802, the stopped stateof the carriage is canceled by setting the direction signal to highlevel and simultaneously setting the brake signal to low level (theperiod D-A in FIG. 4).

Next, in step S803, the PWM signal is output at 80% duty cycle, and thecarriage 3 starts the operating in the forward direction (the period P-Ain FIG. 4). As is obvious from the carriage speed profile of FIG. 4, thecarriage 3 is accelerated. The CPU 101 simultaneously counts the numberof pulses of each encoder signal, and starts calculating the carriagespeed based on the pulse intervals.

In addition, in step S804, the CPU 101 checks whether the carriage speedhas reached a target speed V stored in the recovery unit 120. If it isdetermined that the carriage speed has reached the target speed V, theprocess will advance to step S805 to change the duty cycle of the PWMsignal to 50% to make the carriage 3 move at a constant speed (theperiod P-B in FIG. 4). As is obvious from the carriage speed profile ofFIG. 4, the carriage 3 will shift from moving at an accelerated speed tomoving at a constant speed. In contrast, if it is determined that thecarriage speed has not reached the target speed V, the process willreturn to step S803 to continue the carriage control by maintaining thePWM signal at 80% duty cycle.

In step S806, whether the carriage position has reached a stop startposition P is checked. Note that the stop start position P is calculatedby subtracting a distance to a stop position stored in the ROM 120 froma carriage target stop position Y, which is calculated by the CPU 101from the carriage speed or the printing width. If it is determined herethat the carriage position has not reached the stop start position P,the process will return to step S805 to continue the constant speedmovement control executed on the carriage in a state in which the PWMsignal is maintained at 50% duty cycle. In contrast, if it is determinedthat the carriage position has reached the stop start position P, theprocess will advance to step S807 to stop the operation to move thecarriage 3 by setting the duty cycle of the PWM signal to 20% and thebrake signal to high level (the period P-C in FIG. 4). As is obviousfrom the carriage speed profile of FIG. 4, the carriage 3 will shiftfrom moving at an accelerated speed to moving at a decelerated speed.

In step S808, whether the carriage 3 has stopped is checked. If it isconfirmed, based on the output of the encoder signals, that the positionof the carriage 3 has not changed, that is, the carriage has stopped,the control for moving the carriage in the forward direction will end.In contrast, if it is determined that the carriage 3 has not stopped,the process will return to step S807 to continue the control todecelerate the carriage.

Note that the value of the duty setting of the PWM signal is notparticularly limited since the duty setting will change based on thetarget carriage speed, the acceleration speed during the time ofacceleration/deceleration, or the like. In addition, the procedure ofthe operation to be performed for a movement in the reverse direction isalso similar to that of the operation performed for the movement in theforward direction.

Hence, according to the embodiment described above, by arranging acommon control line, a common control unit, and a common driving unit,it will be possible to reduce the circuit area and to simplify thecontrol method. As a result, good control responsiveness and goodcontrol stability can be obtained even in an arrangement using one setof (two) carriage motors to drive a heavyweight carriage, and it will bepossible to implement a high-speed and high-accuracy carriage drivingoperation.

Note the carriage motor is not limited to a brushless DC motor and maybe, other than a DC motor such as a brushless DC motor, a stepping motoror the like. The form (type) of the carriage motors is not limited aslong as motors that can drive a carriage and motors having similar kindsof driving characteristics are used for both left and right ends.

In addition, although an arrangement in which the control unit 102controls the common driving unit 103 by using the signals of the controlline 110 and the phase information 108 from the carriage motor 104 hasbeen described, it may be arranged so that the control will be performedbased on the phase information from the carriage motor 107.

In addition, as long as identical signals are output to the control line110, it may be arranged so that the signals will be output from the sameterminal or from separate terminals from the CPU 101.

Furthermore, although the embodiment described above has an arrangementin which driving control can be performed easily by arranging so thatthe plurality of carriage motors 104 and 107 each having a drivingpulley 19 will have similar characteristics, the present invention isnot limited to this. For example, the left and right driving pulleys 19may have different diameters from each other or the outputs from thecarriage motor 104 and the carriage motor 107 may differ even if thedriving characteristics of these motors are similar.

Although a single controller and a single motor driver were used in themotor control arrangement of the printing apparatus according to thefirst embodiment shown in FIG. 3, an arrangement that uses motor driverscorresponding to two carriage motors may also be employed. Furthermore,an arrangement using two controllers may also be employed. Twomodifications which are an arrangement that uses a single control unit(controller) and two driving units (motor drivers) and an arrangementthat uses two control units (controllers) and two driving units (motordrivers) will be described hereinafter.

<Modification 1>

FIG. 9 is a block diagram showing the motor control arrangement of aprinting apparatus according to Modification 1 of the first embodiment.Note that in FIG. 9, the same reference numerals denote componentssimilar to those already described with reference to FIG. 3, and adescription thereof will be omitted.

According to FIG. 9, the control unit 102 controls, based on the signalsof the control line 110 and the phase information 108 from the carriagemotor 104, a driving unit (motor driver) 111 and a driving unit (motordriver) 112. Next, the carriage motor 104 and the carriage motor 107perform predetermined operations based on driving signals generatedbased on the ON/OFF states of the FETs of the driving unit 111 and thoseof the driving unit 112.

FIG. 10 is a diagram showing the more specific details of therelationship between the control line 110, the control unit 102, thedriving unit 111, the driving unit 112, and the phase information 108from the carriage motor 104. Note that in FIG. 10, the same referencenumerals denote components similar to those already described withreference to FIG. 6, and a description thereof will be omitted.

Although the control method of the carriage motor of this modificationis similar to that of the first embodiment, the driving unit 111 isconnected to the carriage motor 104 and formed by the power supply linesVM, FETs 131 to 133, and FETs 134 to 136. The driving unit 112 isconnected to the carriage motor 107 and formed by the power supply linesVM, FETs 137 to 139, and FETs 140 to 142. The two driving units have thesame circuit arrangement in this manner.

As shown in FIG. 10, in the arrangement of this modification, thecontrol line 110 and the control unit 102 are arranged in common for thedriving control of the two carriage motors, and each of two drivingunits is connected to a corresponding one of the carriage motors.

By employing such an arrangement, the electric power load on eachdriving unit can be reduced by half, thereby allowing reduction of costsnecessary for measures against heat.

<Modification 2>

FIG. 11 is a block diagram showing the motor control arrangement of aprinting apparatus according to Modification 2 of the first embodiment.Note that in FIG. 11, the same reference numerals denote componentssimilar to those already described with reference FIGS. 3 and 9, and adescription thereof will be omitted.

According to FIG. 11, the CPU 101 controls a control unit (controller)130 and a control unit (controller) 131 by a control line 201 and acontrol line 202, respectively. Note that in this modification, thecontrol lines 201 and 202 include identical signals. The control unit130 and the control unit 131 control the driving unit 111 and thedriving unit 112, respectively, based on signals from the control line201 and the control line 202, the phase information 108 from thecarriage motor 104 and phase information 109 from the carriage motor107. Subsequently, the carriage motor 104 and the carriage motor 107perform predetermined operations based on driving signals generatedbased on the ON/OFF states of the FETs of the driving unit 111 and thoseof the driving unit 112.

FIG. 12 is a diagram showing in the more specific details of therelationship between the control line 201, the control line 202, thecontrol unit 130, the control unit 131, the driving unit 111, thedriving unit 112, the phase information 108 from the carriage motor 104,and the phase information 109 from the carriage motor 107. Note that inFIG. 12, the same reference numerals denote components similar to thosealready described with reference to FIGS. 6 and 10, and a descriptionthereof will be omitted.

The control method of the carriage motors of this modification issimilar to that of the first embodiment, and the arrangements of the twodrivers are similar to those of Modification 1. As shown in FIG. 12, inthe arrangement of this modification, the control line 201 and thecontrol line 202 are arranged in common, and each carriage motor isconnected to a corresponding control unit and a corresponding drivingunit. In addition, the two controllers have the same arrangement.

By employing such an arrangement, the electric power load on eachdriving unit can be reduced by half, thereby allowing reduction of costsnecessary for measures against heat. In addition, in this modification,since control will be performed by inputting each of the pieces of phaseinformation 108 and the phase information 109 of the respective carriagemotors to the corresponding one of the control units, each carriagemotor can be controlled more accurately.

Furthermore, by employing such an arrangement, it will be possible tomake, while using a signal from the same encoder sensor 14, an arbitrarycarriage motor operate by arranging a control line for each carriagemotor. As a result, for example, it will be possible execute control tochange the power ratio (for example, 60:40 or the like) between thecarriage motor 104 and the carriage motor 107, thereby allowing a moreprecise motor control operation to be implemented.

Second Embodiment

Two carriage motors were simultaneously driven in the first embodiment.However, in practice, in a case in which the carriage will not execute ahigh-speed movement, for example, when executing printing up to a speedof 70 ips or when performing an operation other than printing, thecarriage can also be operated by driving one carriage motor while makingthe other carriage motor follow. Hence, in such aforementioned drivingoperation, it is impossible to discriminate whether each carriage motoris operating normally.

Therefore, this embodiment will describe an example in which thecarriage motors will be driven one by one at separate timings to confirmwhether each carriage motor is operating normally.

FIG. 13 is a block diagram showing the motor control arrangement of aprinting apparatus according to the second embodiment. Note that in FIG.13, the same reference numerals denote the same components similar tothose already described with reference to FIG. 3, and a descriptionthereof will be omitted.

As is obvious from comparing FIGS. 13 and 3, the basic arrangement issimilar to the arrangement according to the first embodiment shown inFIG. 3. However, in this case, a switch (SW) 161 and a switch (SW) 162are arranged on a control line between two carriage motors and a drivingunit 103. A CPU 101 will perform ON/OFF control on each of the switch161 and the switch 162 via corresponding individual control lines.

Processing for using such an arrangement to confirm whether each ofcarriage motors 104 and 107 is operating normally will be describednext. A sequence for confirming the operation of each carriage motor isincorporated in an initialization operation performed when the printingapparatus is powered on. The initialization processing is an operationfor confirming whether components inside the printing apparatus arenormal.

FIG. 14 is a flowchart showing a carriage motor confirmation sequence.

By executing this sequence, the carriage motors will be operatedindividually to confirm whether each carriage motor is not operatingabnormally. A detailed description will be given hereinafter withreference to FIG. 2 which shows target positions a, b, and c of acarriage in this sequence.

First, in step S1601, parameters L and R which indicate whether the twocarriage motors are normal or abnormal are reset to L=0 and R=0. Next,in step S1602, in a state in which a carriage 3 is at its movementorigin point (a home position or an initial position) which is indicatedas “0” in FIG. 2, only the carriage motor 104 is driven. Morespecifically, an operation command in which “a” indicated in FIG. 2 isset as a target position and the carriage speed is set to 35 ips isissued and only the switch 161 is set to ON to make the carriage 3operate in the forward direction. Note that in this embodiment, theresolution of the slits formed on a linear scale 13 is 1,200 dpi, andthe target position a corresponds to a point at 2,000 slits (=42.3 mm)from the origin point 0 when measured by the number of slits provided onthe linear scale.

Next, in step S1603, whether the carriage 3 was able to move isconfirmed. Although this is confirmed by determining whether thecarriage 3 was able to move 1,000 (=21.2 mm) slits or more within 5 secof the start of the driving operation of the motor, the presentinvention is not limited to this. For example, it may be confirmed bychecking whether an encoder signal was detected at an expected time atthe target position a. If it is determined here that the carriage 3 wasnot able to move, the process will advance to step S1604 to set L=1, andthe process will subsequently advance to step S1605. In contrast, if itis determined that the carriage 3 was able to move, the parameter L willremain at L=0, and the process will advance to step S1605.

Next, in the process of step S1605, only the carriage motor 107 isdriven. More specifically, an operation command in which “b” indicatedin FIG. 2 is set as a target position and the carriage speed is set to35 ips is issued, and only the switch 162 is set to ON to make thecarriage 3 operate in the forward direction. Note that the targetposition b corresponds to a point at 4,000 slits (=84.7 mm) from theorigin point 0 when measured by the number of slits provided on thelinear scale.

Subsequently, in step S1606, whether the carriage 3 was able to move isconfirmed. This is confirmed by determining whether the carriage 3 wasable to move 1,000 (=21.2 mm) slits or more within 5 sec of the start ofthe driving operation of the motor, the present invention is not limitedto this. For example, it may be confirmed by checking whether an encodersignal was detected at an expected time at the target position b. If itis determined here that the carriage 3 was not able to move, the processwill advance to step S1607 to set R=1, and the process will subsequentlyadvance to step S1608. In contrast, if it is determined that thecarriage 3 was able to move, the parameter R will remain at R=0, and theprocess will advance to step S1608.

Next, in the process of step S1608, whether the values of the twoparameters are L=0 and R=0 is checked. If the two parameters are L=0 andR=0, it will be determined that both the two carriage motors 104 and 107are operating normally, and the confirmation sequence will end. Incontrast, if the two parameters are not L=0 and R=0, the process willadvance to step S1609 to check whether the values of the two parametersare L=1 and R=0.

If the two parameters are L=1 and R=0, the process will advance to stepS1610 to determine that the carriage motor 104 is abnormal, and the userwill be notified of this abnormality. The notification will be performedby displaying a message on an operation panel (not shown) of a printingapparatus 100, by transmitting error information to a host apparatus(not shown) connected to the printing apparatus 100 to display an errormessage on a display of the host apparatus, or the like. For example, afailure in a wiring line to the carriage motor 104, a failure of thecarriage motor 104 itself, or the like can be considered to be a causeof the abnormality in this case.

In contrast, if the two parameters are not L=1 and R=0, the process willadvance to step S1611 to check whether the values of the two parametersare L=0 and R=1. If the two parameters are L=0 and R=1, the process willadvance to step S1612 to determine that the carriage motor 107 isabnormal, and the user will be notified of this abnormality. Thisnotification is performed in a manner similar to the notification methodperformed in step S1610. For example, a failure in a wiring line to thecarriage motor 107, a failure of the carriage motor 107 itself, or thelike can be considered to be a cause of the abnormality in this case.

In contrast, if the two parameters are not L=0 and R=1 (that is, the twoparameters are L=1 and R=1), the process will advance to step S1613 todetermine that the carriage 3 cannot move because an obstacle or thelike is present in the periphery of the carriage 3, and the user will benotified of this determination. This notification is performed in amanner similar to the notification method performed in step S1610.

The confirmation sequence will also be ended after step S1610, stepS1612, or the notification in step S1613.

Note that after step S1610, step S1612, or the notification in stepS1613, the user may turn off the printing apparatus 100 and turn on theprinting apparatus 100 again to cause the initialization operation to beexecuted again. If the abnormality of the carriage motor 104 is unsolvedeven after this operation, the periphery of the carriage motor 104 willbe checked or components will be replaced. On the other hand, if theabnormality of the carriage motor 107 is unsolved even after thisoperation, the periphery of the carriage motor 107 will be checked orcomponents will be replaced. In a case in which the state in which thecarriage cannot move is unsolved, the periphery of the carriage 3 willbe checked or components of the carriage unit will be replaced.

Note that in this embodiment, the operation commands to the carriagemotors 104 and 107 and the comparison of the slit detection result ofthe linear scale 13 are performed to confirm, by issuing a motoroperation command, whether the detection by an encoder sensor 14 haschanged and the carriage 3 can move a predetermined amount or more. Inthis case, while operating the carriage 3 in the forward direction, itwill be possible to make a determination in a continuous operationwithout stopping the carriage 3 for each determination.

Furthermore, the target positions of the carriage and the carriage speeddescribed above are merely examples, and other target positions andanother carriage speed may also be used.

According to the above-described confirmation sequence, in a printingapparatus that uses a plurality of carriage motors to operate acarriage, whether each of the plurality of carriage motors is operatingnormally can be reliably detected without making the carriage operate ata high speed.

<Modification 1>

Another example of confirming whether the individual carriage motors 104and 107 are operating normally will be described here. In this example,whether each carriage motor is abnormal is confirmed after confirmingthat an obstacle is absent in the present in the periphery of thecarriage 3 and operating each carriage motor after using both carriagemotors to operate the carriage 3. Note that in this modification, itwill be assumed that the arrangement shown in FIG. 13 is used as themotor control arrangement of the printing apparatus.

FIG. 15 is a flowchart showing the carriage motor confirmation sequenceaccording to Modification 1 of the second embodiment. A detaileddescription will be given hereinafter with reference to FIG. 2 whichshows the target positions a, b, and c of the carriage in this sequence.Note that in FIG. 15, the same step numbers are used to denote the sameprocessing steps as those already described with reference to FIG. 13,and a description thereof will be omitted.

According to FIG. 15, in step S1602 a, both the carriage motors 104 and107 are driven in a state in which the carriage 3 is at its movementorigin point (the home position or the initial position) which isindicated as “0” in FIG. 2. More specifically, an operation command inwhich “a” indicated in FIG. 2 is set as a target position and thecarriage speed is set to 35 ips is issued, and both of the switches 161and 162 are set to ON to make the carriage 3 operate in the forwarddirection. Note that in this example, the resolution of the slits formedon a linear scale 13 is 1,200 dpi, and the target position a correspondsto a point at 2,000 slits (=42. 3 mm) from the origin point 0 whenmeasured by the number of slits provided on the linear scale.

Next, in step S1603 a, whether the carriage 3 has reached the targetposition a is confirmed. This is confirmed by determining whether thecarriage 3 is within ±30 slits (=±0.625 mm) of the target positionwithin 5 sec. However, the present invention is not limited to this. Forexample, this may be confirmed by checking whether an encoder signal isdetected at an expected time T±Δt at the target position a. If it isdetermined here that the carriage 3 has not reached the target positiona, it will be determined that the carriage 3 is unable to move becausean obstacle is present in the periphery of the carriage 3, the processwill advance to step S1613, and the processing will subsequently end. Incontrast, if it is determined that the carriage 3 has reached the targetposition a, the process will advance to step S1605 a.

In step S1605 a, only the carriage motor 104 is driven. Morespecifically, an operation command in which “b” indicated in FIG. 2 isset as a target position and the carriage speed is set to 35 ips isissued, and only the switch 161 is set to ON to make the carriage 3operate in the forward direction. The target position b corresponds to apoint at 4,000 slits (=84.7 mm) from the origin point 0 when measured bythe number of slits provided on the linear scale. Subsequently, in stepS1606 a, whether the carriage 3 has reached the next target position bis confirmed. This is confirmed by determining whether the carriage 3 iswithin ±30 slits (=±0.625 mm) of the target position within 5 sec.However, the present invention is not limited to this. For example, thismay be confirmed by checking whether an encoder signal is detected atthe expected time T±Δt at the target position b. If it is determinedhere that the carriage 3 has not reached the target position b, theprocess will advance to step S1610, and the processing will subsequentlyend. In contrast, if it is determined that the carriage 3 has reachedthe target position b, the process will advance to step S1606 b.

In step S1606 b, only the carriage motor 107 is driven. Morespecifically, an operation command in which “c” indicated in FIG. 2 isset as a target position and the carriage speed is set to 35 ips isissued, and only the switch 162 is set to ON to make the carriage 3operate in the forward direction. The target position c corresponds to apoint at 6,000 slits (=127 mm) from the origin point 0 when measured bythe number of slits provided on the linear scale. Subsequently, in stepS1606 c, whether the carriage 3 has reached the next target position cis confirmed. This is confirmed by determining whether the carriage 3 iswithin ±30 slits (=±0.625 mm) of the target position within 5 sec.However, the present invention is not limited to this. For example, thismay be confirmed by checking whether an encoder signal is detected atthe expected time T±Δt at the target position c.

If it is determined here that the carriage 3 has not reached the targetposition c, the process will advance to step S1612, and the processingwill subsequently end. In contrast, if it is determined that thecarriage 3 has reached the target position c, the processing will be endbecause it has been confirmed that the carriage motors 104 and 107 areoperating normally.

Therefore, according to the embodiments and the modifications describedabove, even in a printing apparatus that uses a plurality of carriagemotors to operate a carriage, whether each of the plurality of carriagemotors is operating normally can be reliably detected without making thecarriage operate at a high speed.

Note that although this modification employed a confirmation method inwhich the carriage 3 is operated repeatedly in the forward direction, amethod in which the carriage 3 is operated and stopped in the reversedirection after the carriage 3 has been operated and stopped in theforward direction may also be employed.

<Modification 2>

FIG. 16 is a block diagram showing the motor control arrangement of aprinting apparatus according to Modification 2 of the second embodiment.As is obvious from comparing FIGS. 16 and 9, this control arrangement isan arrangement in which switches and control lines have been added tothe motor control arrangement of the printing apparatus according toModification 1 of the first embodiment shown in FIG. 9.

Note that in FIG. 16, the same reference numerals denote componentssimilar to those already described with reference to FIGS. 3 and 9, anda description thereof will be omitted. Even by employing this kind ofarrangement, it will be possible to drive only one of the two carriagemotors 104 and 107.

As shown in FIG. 16, switches (SWs) 177 and 178 are arranged on thecontrol lines from driving units 111 and 112 corresponding to the twocarriage motors, respectively. The CPU 101 can individually executeON/OFF control on each of the switches 177 and 178.

Furthermore, it may be arranged so that the CPU 101 will control thedriving units 111 and 112 individually by arranging switches (SWs) 198and 199 on power supply lines VM of the driving units 111 and 112corresponding to the two carriage motors, respectively. In this manner,it is possible to freely implement the motor control arrangementdepending on the layout of a pattern, the number of switches, and thelike.

By using the motor control arrangement described above, it will bepossible to execute a sequence for confirming individual carriage motorsas described with reference to FIGS. 14 and 15.

<Modification 3>

FIG. 17 is a block diagram showing the motor control arrangement of aprinting apparatus according to Modification 3 of the second embodiment.As is obvious from comparing FIGS. 17 and 11, this control arrangementis an arrangement in which switches and control lines have been added tothe motor control arrangement of the printing apparatus according toModification 2 of the first embodiment shown in FIG. 1.

Note that in FIG. 17, the same reference numerals denote componentssimilar to those already described with reference to FIGS. 3 and 11, anda description thereof will be omitted. Even by employing this kind ofarrangement, it will be possible to drive only one of the two carriagemotors 104 and 107.

As shown in FIG. 17, switches (SWs) 171 and 172 are arranged on thecontrol lines from driving units 111 and 112 corresponding to the twocarriage motors, respectively. The CPU 101 can individually executeON/OFF control on each of the switches 171 and 172.

Furthermore, it may be arranged so that the CPU 101 will control thedriving units 111 and 112 individually by arranging switches (SWs) 181and 182 on the power supply lines VM of the driving units 111 and 112corresponding to the two carriage motors, respectively. In this manner,it is possible to freely implement the motor control arrangementdepending on the layout of a pattern, the number of switches, and thelike.

By using the motor control arrangement described above, it will bepossible to execute a sequence for confirming individual carriage motorsas described with reference to FIGS. 14 and 15.

In addition, in each of the embodiments and the modifications describedabove, it is preferable for a timing belt 7, tubes 73R and 73L, and tubeholding members 78R and 78L to be wound around so as to be approximatelybilaterally symmetrical to the carriage 3. That is, this indicates astate in which these components are wound to have a bilaterallysymmetrical arrangement, upon being viewed from the front and the topdirection with respect to the carriage 3 as the origin, when thecarriage 3 is positioned at the approximate center of its maximummovement range as shown in FIG. 2. Since this will make the load fromthe movement of the carriage in the forward direction and the load fromthe movement of the carriage in the reverse direction be approximatelythe same, the loads on the carriage motors 104 and 107 arranged on theleft side and the right side will also be approximately the same.Driving control can be performed more easily as the outputs from thecarriage motors 104 and 107 become more equal, thus improving controlresponsiveness. Hence, for example, by continuing to use the printingapparatus, it will be possible to maintain an equal output balancebetween the left and right carriage motors even if the outputs of thecarriage motors degrade.

Furthermore, although each of the embodiments and the modificationsdescribed above described an example of a printing apparatus thatperforms printing by reciprocally moving a carriage on which a printheadis mounted, the present invention is not limited to this. The presentinvention can be applied to, for example, a scanner apparatus that readsan image of an original by reciprocally moving a scanner on which acontact image scanner (CIS) is mounted, a multi-function printerincorporating both this scanner apparatus and the printing apparatus,and the like.

The present invention is not limited to the above embodiments andvarious changes and modifications can be made within the spirit andscope of the present invention. Therefore, to apprise the public of thescope of the present invention, the following claims are made.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2020-166108, filed on Sep. 30, 2020 which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A carriage apparatus comprising: a carriageconfigured to reciprocally move in a predetermined direction; a firstmotor arranged on a side of one end of a range of movement of thecarriage and configured to drive the carriage; a second motor arrangedon a side of the other end of the range of movement of the carriage,configured to drive the carriage, and has the same kind of drivingcharacteristics as driving characteristics of the first motor; adetection unit configured to detect a position of the carriage relatedto the predetermined direction; and a control unit configured to controldriving of the first motor and the second motor by feeding back adetection result detected by the detection unit.
 2. The apparatusaccording to claim 1, wherein the detection unit includes a linear scalearranged to extend in a direction of movement of the carriage andincludes slits formed at predetermined intervals, and an encoder sensorarranged on the carriage and configured to detect the position of thecarriage by moving with the carriage and reading the slits on the linearscale.
 3. The apparatus according to claim 1, further comprising: adriving unit configured to drive the first motor and the second motorbased on a control signal output from the control unit, wherein thedriving unit transmits, based on the control signal, a driving signal toeach of the first motor and the second motor.
 4. The apparatus accordingto claim 3, wherein the driving signal generated by the driving unit isgenerated based on the same control signal.
 5. The apparatus accordingto claim 3, wherein one driving unit is arranged in common for the firstmotor and the second motor.
 6. The apparatus according to claim 3,wherein two driving units are arranged in correspondence with the firstmotor and the second motor.
 7. The apparatus according to claim 1,wherein the first motor and the second motor are stopped by a brakesignal output from the control unit.
 8. The apparatus according to claim7, wherein the control unit drives the first motor and the second motorafter canceling the stopped state of the first motor and the secondmotor set by the brake signal.
 9. The apparatus according to claim 1,wherein the control unit performs control to move the carriage from aninitial first position to a predetermined second position by driving atleast one of the first motor and the second motor, and determines, basedon the control result, whether the carriage is operating normally. 10.The apparatus according to claim 9, wherein the control unit determineswhether the first motor is operating normally by driving only the firstmotor and confirming whether the carriage is operating normally underthe control, and the control unit determines whether the second motor isoperating normally by driving only the second motor and confirmingwhether the carriage is operating normally under the control.
 11. Theapparatus according to claim 9, wherein the control unit drives thefirst motor and the second motor to determine whether the carriage isoperating normally under the control.
 12. The apparatus according toclaim 9, further comprising: a notification unit configured to notify,based on the result of the determination, a user of an abnormality inthe operation of the carriage.
 13. The apparatus according to claim 12,wherein the notification unit further notifies the user of anabnormality in one of the first motor and the second motor.
 14. Theapparatus according to claim 9, wherein each of the determination as towhether the carriage is operating normally and the determination as towhether one of the first motor and the second motor is operatingnormally is performed by confirming, after the start of a motor drivingoperation, whether the carriage can move a predetermined distance in apredetermined time.
 15. The apparatus according to claim 9, wherein eachof the determination as to whether the carriage is operating normallyand the determination as to whether one of the first motor and thesecond motor is operating normally is performed by confirming, after thestart of a motor driving operation, whether the carriage has reached thesecond position at a predetermined time.
 16. The apparatus according toclaim 1, wherein one of the first motor and the second motor is made notto operate by a reset signal output from the control unit.
 17. Theapparatus according to claim 1, further comprising: a first switchconfigured to set the driving of the first motor to ON or OFF; and asecond switch configured to set the driving of the second motor to ON orOFF, wherein the control unit controls the first switch and the secondswitch.
 18. The apparatus according to claim 6, further comprising: athird switch and a fourth switch each configured to set a power supplyof a corresponding one of the two driving units to ON or OFF, and thecontrol unit performs control to set each of the third switch and thefourth switch to ON or OFF.
 19. The apparatus according to claim 1,wherein when a belt to be connected to the first motor, the secondmotor, and the carriage and a tube to be attached to the carriage arepositioned at an approximate center of a maximum range of movement whichcan be moved by the carriage, the belt and the tube are wound to beapproximately bilaterally symmetrical when viewed from one of the frontand top direction with respect to the direction of movement of thecarriage.
 20. The apparatus according to claim 1, wherein the firstmotor and the second motor are one of a set of DC motors having the samekind of driving characteristics and a set of stepper motors having thesame kind of driving characteristics.
 21. A printing apparatuscomprising: a carriage apparatus defined in claim 1; and a printheadmounted on a carriage.
 22. The apparatus according to claim 21, furthercomprising: a tube connected to the printhead; and a tube holding memberconfigured to move together with the printhead and to guide the tube.23. The printing apparatus according to claim 21, further comprising: anink tank configured to supply ink to the printhead, wherein a referenceof a position of the carriage is on a side of the ink tank.
 24. Acontrol method of a carriage apparatus that includes a carriageconfigured to reciprocally move in a predetermined direction, a firstmotor arranged on a side of one end of a range of movement of thecarriage and configured to drive the carriage, and a second motorarranged on a side of the other end of the range of movement of thecarriage, configured to drive the carriage, and has the same kind ofdriving characteristics as driving characteristics of the first motor,the method comprising: detecting a position of the carriage related tothe predetermined direction; and controlling driving of the first motorand the second motor by feeding back a detection result detected in thedetecting.